Carburetor



Feb. 17, 1931. C. F. ROBBlNS 1,793,250

CARBURETOR Filed sept. 19 1928 INVENTOR UM fn/@ By Attorneys,

Patented Feb. 17, '1931 UNITED STATES CHABLE F. ROBBINS, F GLENOBA,NEWK'YORK CABIBURETOR Application led September 19, 1928. Serial No.306,796.

This invention relates to carburetors for internal combustion engines orthe like, being particularly directed to a thermostatic con,-

trol of the mixture. More specifically the invention is directed tocarburetors of the well-known Marvel type, wherein the air valve islocated within the mixing chamber of the carburetor, which air valvemoves against the pressure of a spring, being con- 10 nected to adash-pot which also controls the action ofthe valve.

' In carburetors of this type there is usually a main air inlet, a partof the intake of-which is xed and serves to draw the asoline up throughthe main nozzle. T e springactuated valve before referred to controlsonly a part of the How through the main inlet. According tothe presentinvention I provide means for thermostatically controlling suchinternally arranged air valves whereby the proportions of air andgasoline may be maintained substantially constant at various degrees ofloutside temperature. According to the invention in its preferred form Iintroduce a member constructed of thermostatic metal between the airvalve and the dash-pot, whereby a given suction will open the air valveto a lesser degree at colder temperatures.

Referring to the drawings wherein I havev illustrated one of the formsof the wellknown forms of Marvel carburetor: v

Figure 1 is an elevation partly in vertical section of the carburetorequipped with my improvement. v

Fig. 2 is an elevation of the air valve taken ap roximately on the line2-2 in Figure 1.

ig. 3 is a section of the thermostat shown as applied to the air valve.

F1g. 4 is a side elevation of the air valve with its dashot pistonshowing a slight modification o Figure 1.

Referring to the drawings, let A indicate lthe carburetor as a whole,having an air inlet B which is designed to su ply substantially all ofthe air whlch passes t rough the carbu- "reton A is the throttle, and Bis the usual choke. To the right of the air -inlet and close against thewall C is a nozzle D pro- 50 vided with a venturi E, the nozzle being inthe piston O moving in a cylinder Q, piston communication with thepassage F leading from a ioat chamber G. A substantially constant feedof gasoline takes place from the float chamber, the float operating aneedle H which controls the valve opening I leading to Qtgie` supply,the inlet `of which is indicated at A The automatic valve control forthe air i's indicated at K, and isshown Aas a valve leading to themixing chamber L, the valve being pivoted on a shaft M and being soproportioned at its lower'and rearward end that there is a constantpassage around the valve indicated by the arrow and unaected by thevalve. This passage isrelied u on for the primary jet, the air owing upt irough the venturi and around the jet and serving to maintain asuitable mixture in the mixing chamber L when the engine is idling `orthe car-proceeding at low speed.

An auxiliary jet isl employed for higher speeds, said jet beingindicated by the reference letter- N and leading to a passage which isnot shown in the drawing, but which is controlledb the throttle A insuch manner that as t e speed of the engine increases greater quantitiesof gasoline are sucked up through the auxiliary jet. Accompanyingthis isof course, an opening of the automatic valve which opens to a greater orless extent depending upon the suction of the engine. f

'.The air controlling valve K is usually connected directly with apiston O by a link P,

e5 and c linder constituting a dashot, and there ingV normally a springR which loads the valve andl tends to move it back to its closedposition.

According tothe present invention in its preferred form, I interposebetween the dash-v pot piston O\ and valve K a'thermostat T, andthis isbest accomplished by mounting the thermostat between the valve and theendof the link P. The thermostat as shown is formed b a loop of flatmetal which may be regarde as the usual bimetallic thermostatic metal,the thermostat being reversel arranged, that is to say, so that the twoen s of the thermostat tend to approach each other valve by means ofrivets U and pivotally attached to the link by bifurcating thethermostat at its ends and forming an eye in 'each bifurcation, the twolegs straddling the link P which is aperturedto receive a cotter pin orthe like V.

While the thermostat may form the sole connection between the link andthe valve, as illustrated in Fig. 4, I prefer to introduce a spring WVwithin the thermostatic loop so as lto partially counterbalance thepressure of the spring R, as illustrated in Figures 1 and 3. By thismeans the thermostat is not subjected to the entire pressure of thespring R, while atrthe same time it is easily affected by thetemperature of the air passing through the carburetor. The spring 'W mayconsist of a single piece of wire suitably bent, the two ends of whichmay be removably connected with the thermostat by passing through holesX formed in the latter.

It will be observed that by locating the thermostat in the manner'shown,it lies in the path of the idling or slow speed current of air ormixture as 'it passes through and around the venturi E. The thermostatis, therefore, admirably located to proportion the air in accordancewith the precise temperature of air which is passing into theearburetor.

While I haveshown and described several forms of the invention, it willbe understood that I do not wish to be limited thereby, since variouschanges may be made therein without departing from the spirit of theinvention.

What I claim is:

1. A carburetor having an air yvalve and dash-pot comprising a cylinderand a piston for controlling the movement of said air valve, acompression link directly connected with said piston, and a thermostaticelement between said link and said air valve.

2. A carburetor having an air valve and means for opposing its movement,a thermostat connecting said air valve with said means, and a springarranged to reinforce said thermostat against the eect of said opposingmeans. Y

3. A carburetor having' an air inlet and a primary jet operated by aportion of the air entering said air inlet, an inclined valvecontrolling the remainder of the air admitted through said air inlet, adash-'pot having a spring for opposing the movement of said valve, alink connected with said dash-pot body, and a loop-shaped thermostat,one end of which is connected to the valve, and the other end of whichis connected to said link, a spring arranged within the loop of thethermostat for opposing its collapse.

4. A carburetor'having an air inlet, a primary jet operated by a portion'of the air entering said air inlet,v an auxiliary jet, an inclinedvalve controlling a portion ofthe air entering said inlet, and arrangedabove said auxiliary jet, a dashpot disposed approximately at a rightangle to said inclined valve, a spring in said dashpot, a link connectedat one end with said dashpot body, and at the other end with said valve,the connection between the valve and link being a thermostat.

5. A carburetor having an air valve, means for opposing its movement,and a loop thermostat connecting said air valve with said means, and aspring tending to reinforce said thermostat against the effect of saidopposing means. Y t

6. A carburetor having an air valve, means for opposing its movement,and a loopl thermostat Vconnecting said air valve with sai-d means, anda spring also connecting said air valve with said means, said springtending y spring for closing it, a thermostat arrangedv between said airvalve' and said spring, and

valve and said spring sol as to relieve the thermostat of a portion ofthe thrust of said first-named spring.

In witness whereof, I havehereunto signed my name. c

CHARLES F. ROBBINS.

a second. spring arranged between said air

